The present invention relates to a temperature control system for reducing heat generated by a machine tool cutting a workpiece. In particular, a turret-lathe coolant system is disclosed that can be retro-fitted onto a turret lathe, to selectively direct a stream of coolant fluid to an interface between the workpiece and only the specific tool in contact with the workpiece.
Turret lathes enhance efficiency of machining metal by permitting combined, multiple and successive cuts on a metal workpiece by different tools with only one "chucking" or setup of the workpiece in the lathe. Typically, the lathe is setup to rotatably secure the workpiece in a specific position. Next, a plurality of cutting tools on a rotatable turret are indexed to working positions with respect to the workpiece. The lathe then machines the workpiece by directing the turret to selectively move along a longitudinal (or "X") axis and/or a transverse (or "Z") axis until a first tool removes a specified amount of metal from the rotating workpiece. The turret then moves along the "X" and/or "Z" axis while rotating to position a second tool in contact with the workpiece, and so on, until all the indexed tools on the turret have cut the workpiece. For example, a hole in the workpiece may be drilled, bored and reamed at one chucking, by three different tools.
Contact between the workpiece and the metal cutting tools necessarily generates heat, which must be controlled to prevent metallurgical damage to the workpiece and tool. To control that heat, traditional turret-lathe coolant systems simply utilize a plurality of semi-rigid, adjustable hoses to direct a stream of coolant fluid at contact points between the cutting tools and the workpiece. The fluid removes excess heat while lubricating the workpiece and tool, thereby preventing damage. Such a system, however, is very inefficient, because turret lathes involve numerous contact points. Consequently, to cover all the contact points, a great deal of coolant fluid is wasted, because it is needlessly splashed at points on the workpiece that do not require cooling. Such fluid is not only expensive, but is increasingly considered a hazardous-waste material. Disposal costs of machine-tool coolant fluids frequently exceed purchase costs.
Many attempts have been made to increase the efficiency of turret-lathe coolant systems. Two such attempts are shown in U.S. Pat. No. 3,726,363 to Sussman, and in U.S. Pat. No. 4,164,879 to Martin. Both Sussman and Martin show turret-coolant systems that include a specific coolant line or conduit for each tool on the turret, so that fluid can be specifically directed to the contact points between the cutting tools and the workpiece. Additionally, both systems include a valve mechanism that permits coolant fluid to only flow along the turret to the cutting tool positioned to contact the workpiece, while prohibiting fluid from flowing to the other cutting tools on the turret.
The valve mechanisms in both Sussman and Martin, however, require that the turret be especially adapted so that a non-rotatable coolant-fluid distribution member is integrally affixed within the turret, in alignment with the rotational axis of the turret. Consequently, known high efficiency turret-lathe coolant systems require custom designed turrets. Therefore, due to inherent structural limitations, existing turret-lathe coolant systems cannot be retro-fitted onto existing turret lathes.
Accordingly, it is the general object of the present invention to provide an improved turret-lathe coolant system that overcomes the problems of the prior art.
It is a more specific object to provide a turret-lathe coolant system that can be retro-fitted onto existing turret lathes.
It is another specific object to provide a turret-lathe coolant system that can be utilized with existing turret lathes without having to modify the existing lathes.
It is yet another specific object to provide a turret-lathe coolant system that is more economical to produce, safer, and more reliable than existing coolant systems.
The above and other objects and advantages of this invention will become more readily apparent when the following description is read in conjunction with the accompanying drawings.